As far as I know, Kamui is a chain sports facility/shop that has various artificial slopes throughout Japan. Misaka is no exception. Nestled in the bosom of low mountains/hills in Yamanashi, it's pretty much an artificial slope placed outdoors. Right next to the ski field there is said to be an indoor half-pipe, which I didn't know existed until I was on the bus heading home.
In early March, the artificial snow was barely holding and